Microsporidium seriolae and Probable Philometroides seriolae Infection in Yellowtail Amberjack Seriola aureovittata

Abstract

Wild, one-year yellowtail amberjack Seriola aureovittata (n = 13) were examined for parasites after about one month culture in Nagasaki and Kagoshima Prefectures, Japan. ​All fish were infected with the microsporidian Microsporidium seriolae (all qPCR positive; 11 with cysts in the skeletal muscle, four with cysts in the heart as well). ​Considering fish size, culture period, and time required for cyst formation, it is assumed that the fish had been infected with the microsporidian in the wild. ​Additionally, two fish were infected with a nematode in the skeletal muscle, tentatively identified as Philometroides seriolae, which had been recorded only from S. quinqueradiata.